Pressure-induced transformation plasticity of H(2)O ice.

Transformation plasticity is a deformation mechanism which occurs during phase transformation of an externally stressed material. Pressure-induced transformation plasticity of ice could be relevant to the geology of the moons of the outer solar system, and has long been postulated to occur in olivine in the earth's interior. In the present work, ice specimens were subjected to isostatic pressure cycling between 0 and 300 MPa to induce reversible polymorphic transformation between ice I and II at 230 K. When a small uniaxial compressive stress was applied during cycling, the specimens exhibited a compressive strain (as large as 18.5% after a single cycle) proportional to the applied stress, in agreement with observations and theory for transformation plasticity of metals induced by polymorphic thermal cycling.